In grass surfaces such as garden facilities having ornamental grass or in sport fields, an unwanted growth especially of moss, creeper plants or the like can develop between the grass blades. This plant material tends to displace the grass plants in an unwanted manner and, as a consequence thereof, the occasional treatment or processing with a work apparatus can be required.
Handheld, motor-driven work apparatus are known which have a processing roller driven in rotation. The processing roller can be a tine roller with tines for removing moss, a cultivating roller or a scarifier roller for ground treatment, a roller-shaped cleaning brush or the like. In lieu of the processing roller, disc-shaped work tools can be provided such as star-shaped cultivating blades or cutting blades. In the example of a tine roller for moss removal, the tine roller is provided with a plurality of tines which are held by tine carriers between two end carrier plates. For processing grass surfaces, rotation is imparted to the tine roller by means of the drive motor and the tine roller is guided over the grass surface to be treated with its rotational axis lying parallel to the surface. The elastic tines rotate with the tine roller and comb through the grass surface and rake the loose vegetation out which has formed between the grass blades. The raked-out plant material is flung away because of the centrifugal force of the rotating tine roller.
Depending upon the processing conditions, long fiber plant material such as cut long grass blades, creeper vine plants or the like can also be taken up by the tine roller in addition to loose moss. The long fiber plant material tends to get caught in the tines of the tine roller in such a manner that it cannot be flung away.
Rotation is imparted to the tine roller via drive means such as a drive transmission mounted at a front end. The drive means include fixed housing components or the like with reference to which the tine roller executes a relative rotation. Long fiber plant material, which rolls up on the tine roller in an unwanted manner, can seat between the tine roller and the drive transmission thereby impeding the rotational movement of the tine roller. The rotational movement of the tine roller supports a winding pull-in of the plant material into the intermediate space at the side of the drive transmission. A hardening of the plant material occurs. With increasing hardening, the resistance to rotation of the tine roller increases. This can lead to a thermal and/or mechanical overload of the drive train and especially of the drive transmission. Comparative problems can also occur in the remaining above-mentioned embodiments of the work apparatus.